Fri, 13 Apr 2012 01:59:38 +0200
7160728: Introduce an extra logging level for G1 logging
Summary: Added log levels "fine", "finer" and "finest". Let PrintGC map to "fine" and PrintGCDetails map to "finer". Separated out the per worker information in the G1 logging to the "finest" level.
Reviewed-by: stefank, jwilhelm, tonyp, johnc
1 /*
2 * Copyright (c) 2001, 2012, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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5 * This code is free software; you can redistribute it and/or modify it
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7 * published by the Free Software Foundation.
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10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
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23 */
25 #include "precompiled.hpp"
26 #include "classfile/javaClasses.hpp"
27 #include "classfile/symbolTable.hpp"
28 #include "classfile/systemDictionary.hpp"
29 #include "classfile/vmSymbols.hpp"
30 #include "code/codeCache.hpp"
31 #include "code/icBuffer.hpp"
32 #include "gc_implementation/g1/g1Log.hpp"
33 #include "gc_implementation/g1/g1MarkSweep.hpp"
34 #include "memory/gcLocker.hpp"
35 #include "memory/genCollectedHeap.hpp"
36 #include "memory/modRefBarrierSet.hpp"
37 #include "memory/referencePolicy.hpp"
38 #include "memory/space.hpp"
39 #include "oops/instanceRefKlass.hpp"
40 #include "oops/oop.inline.hpp"
41 #include "prims/jvmtiExport.hpp"
42 #include "runtime/aprofiler.hpp"
43 #include "runtime/biasedLocking.hpp"
44 #include "runtime/fprofiler.hpp"
45 #include "runtime/synchronizer.hpp"
46 #include "runtime/thread.hpp"
47 #include "runtime/vmThread.hpp"
48 #include "utilities/copy.hpp"
49 #include "utilities/events.hpp"
51 class HeapRegion;
53 void G1MarkSweep::invoke_at_safepoint(ReferenceProcessor* rp,
54 bool clear_all_softrefs) {
55 assert(SafepointSynchronize::is_at_safepoint(), "must be at a safepoint");
57 SharedHeap* sh = SharedHeap::heap();
58 #ifdef ASSERT
59 if (sh->collector_policy()->should_clear_all_soft_refs()) {
60 assert(clear_all_softrefs, "Policy should have been checked earler");
61 }
62 #endif
63 // hook up weak ref data so it can be used during Mark-Sweep
64 assert(GenMarkSweep::ref_processor() == NULL, "no stomping");
65 assert(rp != NULL, "should be non-NULL");
66 assert(rp == G1CollectedHeap::heap()->ref_processor_stw(), "Precondition");
68 GenMarkSweep::_ref_processor = rp;
69 rp->setup_policy(clear_all_softrefs);
71 // When collecting the permanent generation methodOops may be moving,
72 // so we either have to flush all bcp data or convert it into bci.
73 CodeCache::gc_prologue();
74 Threads::gc_prologue();
76 // Increment the invocation count for the permanent generation, since it is
77 // implicitly collected whenever we do a full mark sweep collection.
78 sh->perm_gen()->stat_record()->invocations++;
80 bool marked_for_unloading = false;
82 allocate_stacks();
84 // We should save the marks of the currently locked biased monitors.
85 // The marking doesn't preserve the marks of biased objects.
86 BiasedLocking::preserve_marks();
88 mark_sweep_phase1(marked_for_unloading, clear_all_softrefs);
90 mark_sweep_phase2();
92 // Don't add any more derived pointers during phase3
93 COMPILER2_PRESENT(DerivedPointerTable::set_active(false));
95 mark_sweep_phase3();
97 mark_sweep_phase4();
99 GenMarkSweep::restore_marks();
100 BiasedLocking::restore_marks();
101 GenMarkSweep::deallocate_stacks();
103 // We must invalidate the perm-gen rs, so that it gets rebuilt.
104 GenRemSet* rs = sh->rem_set();
105 rs->invalidate(sh->perm_gen()->used_region(), true /*whole_heap*/);
107 // "free at last gc" is calculated from these.
108 // CHF: cheating for now!!!
109 // Universe::set_heap_capacity_at_last_gc(Universe::heap()->capacity());
110 // Universe::set_heap_used_at_last_gc(Universe::heap()->used());
112 Threads::gc_epilogue();
113 CodeCache::gc_epilogue();
114 JvmtiExport::gc_epilogue();
116 // refs processing: clean slate
117 GenMarkSweep::_ref_processor = NULL;
118 }
121 void G1MarkSweep::allocate_stacks() {
122 GenMarkSweep::_preserved_count_max = 0;
123 GenMarkSweep::_preserved_marks = NULL;
124 GenMarkSweep::_preserved_count = 0;
125 }
127 void G1MarkSweep::mark_sweep_phase1(bool& marked_for_unloading,
128 bool clear_all_softrefs) {
129 // Recursively traverse all live objects and mark them
130 TraceTime tm("phase 1", G1Log::fine() && Verbose, true, gclog_or_tty);
131 GenMarkSweep::trace(" 1");
133 SharedHeap* sh = SharedHeap::heap();
135 sh->process_strong_roots(true, // activeate StrongRootsScope
136 true, // Collecting permanent generation.
137 SharedHeap::SO_SystemClasses,
138 &GenMarkSweep::follow_root_closure,
139 &GenMarkSweep::follow_code_root_closure,
140 &GenMarkSweep::follow_root_closure);
142 // Process reference objects found during marking
143 ReferenceProcessor* rp = GenMarkSweep::ref_processor();
144 assert(rp == G1CollectedHeap::heap()->ref_processor_stw(), "Sanity");
146 rp->setup_policy(clear_all_softrefs);
147 rp->process_discovered_references(&GenMarkSweep::is_alive,
148 &GenMarkSweep::keep_alive,
149 &GenMarkSweep::follow_stack_closure,
150 NULL);
152 // Follow system dictionary roots and unload classes
153 bool purged_class = SystemDictionary::do_unloading(&GenMarkSweep::is_alive);
154 assert(GenMarkSweep::_marking_stack.is_empty(),
155 "stack should be empty by now");
157 // Follow code cache roots (has to be done after system dictionary,
158 // assumes all live klasses are marked)
159 CodeCache::do_unloading(&GenMarkSweep::is_alive,
160 &GenMarkSweep::keep_alive,
161 purged_class);
162 GenMarkSweep::follow_stack();
164 // Update subklass/sibling/implementor links of live klasses
165 GenMarkSweep::follow_weak_klass_links();
166 assert(GenMarkSweep::_marking_stack.is_empty(),
167 "stack should be empty by now");
169 // Visit memoized MDO's and clear any unmarked weak refs
170 GenMarkSweep::follow_mdo_weak_refs();
171 assert(GenMarkSweep::_marking_stack.is_empty(), "just drained");
173 // Visit interned string tables and delete unmarked oops
174 StringTable::unlink(&GenMarkSweep::is_alive);
175 // Clean up unreferenced symbols in symbol table.
176 SymbolTable::unlink();
178 assert(GenMarkSweep::_marking_stack.is_empty(),
179 "stack should be empty by now");
181 if (VerifyDuringGC) {
182 HandleMark hm; // handle scope
183 COMPILER2_PRESENT(DerivedPointerTableDeactivate dpt_deact);
184 gclog_or_tty->print(" VerifyDuringGC:(full)[Verifying ");
185 Universe::heap()->prepare_for_verify();
186 // Note: we can verify only the heap here. When an object is
187 // marked, the previous value of the mark word (including
188 // identity hash values, ages, etc) is preserved, and the mark
189 // word is set to markOop::marked_value - effectively removing
190 // any hash values from the mark word. These hash values are
191 // used when verifying the dictionaries and so removing them
192 // from the mark word can make verification of the dictionaries
193 // fail. At the end of the GC, the orginal mark word values
194 // (including hash values) are restored to the appropriate
195 // objects.
196 Universe::heap()->verify(/* allow dirty */ true,
197 /* silent */ false,
198 /* option */ VerifyOption_G1UseMarkWord);
200 G1CollectedHeap* g1h = G1CollectedHeap::heap();
201 gclog_or_tty->print_cr("]");
202 }
203 }
205 class G1PrepareCompactClosure: public HeapRegionClosure {
206 G1CollectedHeap* _g1h;
207 ModRefBarrierSet* _mrbs;
208 CompactPoint _cp;
209 HumongousRegionSet _humongous_proxy_set;
211 void free_humongous_region(HeapRegion* hr) {
212 HeapWord* end = hr->end();
213 size_t dummy_pre_used;
214 FreeRegionList dummy_free_list("Dummy Free List for G1MarkSweep");
216 assert(hr->startsHumongous(),
217 "Only the start of a humongous region should be freed.");
218 _g1h->free_humongous_region(hr, &dummy_pre_used, &dummy_free_list,
219 &_humongous_proxy_set, false /* par */);
220 hr->prepare_for_compaction(&_cp);
221 // Also clear the part of the card table that will be unused after
222 // compaction.
223 _mrbs->clear(MemRegion(hr->compaction_top(), end));
224 dummy_free_list.remove_all();
225 }
227 public:
228 G1PrepareCompactClosure(CompactibleSpace* cs)
229 : _g1h(G1CollectedHeap::heap()),
230 _mrbs(G1CollectedHeap::heap()->mr_bs()),
231 _cp(NULL, cs, cs->initialize_threshold()),
232 _humongous_proxy_set("G1MarkSweep Humongous Proxy Set") { }
234 void update_sets() {
235 // We'll recalculate total used bytes and recreate the free list
236 // at the end of the GC, so no point in updating those values here.
237 _g1h->update_sets_after_freeing_regions(0, /* pre_used */
238 NULL, /* free_list */
239 NULL, /* old_proxy_set */
240 &_humongous_proxy_set,
241 false /* par */);
242 }
244 bool doHeapRegion(HeapRegion* hr) {
245 if (hr->isHumongous()) {
246 if (hr->startsHumongous()) {
247 oop obj = oop(hr->bottom());
248 if (obj->is_gc_marked()) {
249 obj->forward_to(obj);
250 } else {
251 free_humongous_region(hr);
252 }
253 } else {
254 assert(hr->continuesHumongous(), "Invalid humongous.");
255 }
256 } else {
257 hr->prepare_for_compaction(&_cp);
258 // Also clear the part of the card table that will be unused after
259 // compaction.
260 _mrbs->clear(MemRegion(hr->compaction_top(), hr->end()));
261 }
262 return false;
263 }
264 };
266 // Finds the first HeapRegion.
267 class FindFirstRegionClosure: public HeapRegionClosure {
268 HeapRegion* _a_region;
269 public:
270 FindFirstRegionClosure() : _a_region(NULL) {}
271 bool doHeapRegion(HeapRegion* r) {
272 _a_region = r;
273 return true;
274 }
275 HeapRegion* result() { return _a_region; }
276 };
278 void G1MarkSweep::mark_sweep_phase2() {
279 // Now all live objects are marked, compute the new object addresses.
281 // It is imperative that we traverse perm_gen LAST. If dead space is
282 // allowed a range of dead object may get overwritten by a dead int
283 // array. If perm_gen is not traversed last a klassOop may get
284 // overwritten. This is fine since it is dead, but if the class has dead
285 // instances we have to skip them, and in order to find their size we
286 // need the klassOop!
287 //
288 // It is not required that we traverse spaces in the same order in
289 // phase2, phase3 and phase4, but the ValidateMarkSweep live oops
290 // tracking expects us to do so. See comment under phase4.
292 G1CollectedHeap* g1h = G1CollectedHeap::heap();
293 Generation* pg = g1h->perm_gen();
295 TraceTime tm("phase 2", G1Log::fine() && Verbose, true, gclog_or_tty);
296 GenMarkSweep::trace("2");
298 FindFirstRegionClosure cl;
299 g1h->heap_region_iterate(&cl);
300 HeapRegion *r = cl.result();
301 CompactibleSpace* sp = r;
302 if (r->isHumongous() && oop(r->bottom())->is_gc_marked()) {
303 sp = r->next_compaction_space();
304 }
306 G1PrepareCompactClosure blk(sp);
307 g1h->heap_region_iterate(&blk);
308 blk.update_sets();
310 CompactPoint perm_cp(pg, NULL, NULL);
311 pg->prepare_for_compaction(&perm_cp);
312 }
314 class G1AdjustPointersClosure: public HeapRegionClosure {
315 public:
316 bool doHeapRegion(HeapRegion* r) {
317 if (r->isHumongous()) {
318 if (r->startsHumongous()) {
319 // We must adjust the pointers on the single H object.
320 oop obj = oop(r->bottom());
321 debug_only(GenMarkSweep::track_interior_pointers(obj));
322 // point all the oops to the new location
323 obj->adjust_pointers();
324 debug_only(GenMarkSweep::check_interior_pointers());
325 }
326 } else {
327 // This really ought to be "as_CompactibleSpace"...
328 r->adjust_pointers();
329 }
330 return false;
331 }
332 };
334 void G1MarkSweep::mark_sweep_phase3() {
335 G1CollectedHeap* g1h = G1CollectedHeap::heap();
336 Generation* pg = g1h->perm_gen();
338 // Adjust the pointers to reflect the new locations
339 TraceTime tm("phase 3", G1Log::fine() && Verbose, true, gclog_or_tty);
340 GenMarkSweep::trace("3");
342 SharedHeap* sh = SharedHeap::heap();
344 sh->process_strong_roots(true, // activate StrongRootsScope
345 true, // Collecting permanent generation.
346 SharedHeap::SO_AllClasses,
347 &GenMarkSweep::adjust_root_pointer_closure,
348 NULL, // do not touch code cache here
349 &GenMarkSweep::adjust_pointer_closure);
351 assert(GenMarkSweep::ref_processor() == g1h->ref_processor_stw(), "Sanity");
352 g1h->ref_processor_stw()->weak_oops_do(&GenMarkSweep::adjust_root_pointer_closure);
354 // Now adjust pointers in remaining weak roots. (All of which should
355 // have been cleared if they pointed to non-surviving objects.)
356 g1h->g1_process_weak_roots(&GenMarkSweep::adjust_root_pointer_closure,
357 &GenMarkSweep::adjust_pointer_closure);
359 GenMarkSweep::adjust_marks();
361 G1AdjustPointersClosure blk;
362 g1h->heap_region_iterate(&blk);
363 pg->adjust_pointers();
364 }
366 class G1SpaceCompactClosure: public HeapRegionClosure {
367 public:
368 G1SpaceCompactClosure() {}
370 bool doHeapRegion(HeapRegion* hr) {
371 if (hr->isHumongous()) {
372 if (hr->startsHumongous()) {
373 oop obj = oop(hr->bottom());
374 if (obj->is_gc_marked()) {
375 obj->init_mark();
376 } else {
377 assert(hr->is_empty(), "Should have been cleared in phase 2.");
378 }
379 hr->reset_during_compaction();
380 }
381 } else {
382 hr->compact();
383 }
384 return false;
385 }
386 };
388 void G1MarkSweep::mark_sweep_phase4() {
389 // All pointers are now adjusted, move objects accordingly
391 // It is imperative that we traverse perm_gen first in phase4. All
392 // classes must be allocated earlier than their instances, and traversing
393 // perm_gen first makes sure that all klassOops have moved to their new
394 // location before any instance does a dispatch through it's klass!
396 // The ValidateMarkSweep live oops tracking expects us to traverse spaces
397 // in the same order in phase2, phase3 and phase4. We don't quite do that
398 // here (perm_gen first rather than last), so we tell the validate code
399 // to use a higher index (saved from phase2) when verifying perm_gen.
400 G1CollectedHeap* g1h = G1CollectedHeap::heap();
401 Generation* pg = g1h->perm_gen();
403 TraceTime tm("phase 4", G1Log::fine() && Verbose, true, gclog_or_tty);
404 GenMarkSweep::trace("4");
406 pg->compact();
408 G1SpaceCompactClosure blk;
409 g1h->heap_region_iterate(&blk);
411 }
413 // Local Variables: ***
414 // c-indentation-style: gnu ***
415 // End: ***